AP-Micro Viral Pathogenesis 3

Question 1

Which type of viral infection is characterized by a long incubation period and slow progressive disease?

Accepted Answer

Slow viral infection

Answer

Slow viral infections, such as those caused by prions or subacute sclerosing panencephalitis (SSPE) from measles virus, have incubation periods of years before symptoms appear.

Question 2

What is the primary reason RNA viruses mutate more rapidly than DNA viruses?

Accepted Answer

RNA-dependent RNA polymerases lack proofreading ability

Answer

RNA-dependent RNA polymerases (RdRp) lack 3'-to-5' exonuclease proofreading activity, leading to error rates ~10,000 times higher than DNA polymerases.

Question 3

How does poliovirus cause paralysis in infected individuals?

Accepted Answer

By destroying anterior horn motor neurons in the spinal cord

Answer

Poliovirus selectively infects and destroys lower motor neurons in the anterior horn of the spinal cord, causing flaccid paralysis in the affected limbs.

Question 4

Which viral pathogenesis mechanism is exemplified by EBV-associated Burkitt's lymphoma?

Accepted Answer

Transformation via viral oncoproteins disrupting cell cycle control

Answer

EBV encodes oncoproteins (e.g., LMP1) that mimic activated growth receptors, driving uncontrolled B-cell proliferation and contributing to Burkitt's lymphoma development.

Question 5

What is a cytokine storm, and why is it particularly dangerous in viral pathogenesis?

Accepted Answer

Dysregulated overproduction of cytokines causing widespread tissue damage

Answer

A cytokine storm is an excessive, uncontrolled release of pro-inflammatory cytokines that damages host tissues and organs, sometimes more severely than the virus itself.

AP Practice Test

AP Practice Test

AP-Micro Viral Pathogenesis 3